%BND_DIRICH%

Dirichlet velocity boundary condition

Dirichlet (first-type) boundary condition for velocities.

BC_v($xyz$) = (%BND_DIRICH%, $ v_x$, $ v_y$, $ v_z$)

Sets the velocity at the boundary to a fixed value or user-defined equation:

\begin{align} \mathbf{v} = \mathbf{v}_\text{user}\end{align}